Valves are important components in processing systems by means of which flows of product media are directed through piping systems in the product-conducting system. The directing effect is based on the switching function of the valves.
A valve has a valve housing having at least one first port and one second port. In the valve of a generic type, a closing member arrangement with a closing member is provided that is movable along an axial direction. Associated with this axial mobility, the valve can be brought into a closed position in which it interacts sealingly with a valve seat arranged between the ports whereby a fluid connection between the first and second ports is blocked. The axial movement of the closing member can be instigated outside of the valve housing. Generally, a pressurizing medium-operated drive is used in which the pressurizing medium exerts pressure on a piston against the restoring force of a spring.
Particular demands are placed on the valve in aseptic applications such as in the food industry. In such applications, the contact of the product with the surrounding air is to be avoided since bacteria and germs can otherwise be introduced into the product. The design of the seal in the valve is correspondingly complex. Sealing the closing member arrangement against the surroundings of the housing is important, particularly where the closing member arrangement is connected to the drive.
DE 102007014282 A1 proposes a fluid-impermeable diaphragm that is held, on the one hand, with a sealing effect on the closing member arrangement and, on the other hand, on a valve-housing-side holding arrangement. The holding arrangement has a clamping gap aligned obliquely to the axial direction. The diaphragm comprises a clamping section running within this clamping gap and a central opening which the closing member arrangement penetrates. The sealing effect results from the central opening being held on the closing member arrangement and the clamping section being held in the clamping gap. In contrast to known materials based on elastomers, this diaphragm is produced from a dimensionally-stable plastic that is heat-resistant up to at least approximately 130° C. This yields constant dimensions under operating conditions, especially operating pressure and operating temperature. Along with clamping the diaphragm in the clamping gap, a high storage stability and an overall effective seal result.
DE 102007014282 A1 teaches further improving the seal by providing a projection in the clamping gap that increases the clamping force.